The latest Suunto Dive Manager for Mac is available for download from its official website. On the same website, the developers posted the minimum requires that you have to meet before installing the software and they are as follows: The minimum OS requirements are: Mac 10.7 / Windows XP. As you can see, your Mac needs to have Mac OSX 10.7 installed. That's Mac OSX Lion based on the version number.
Note: Check and apply all the available updates for your OS installation before installing the software.